Simplex Axle pump

Yes, that's the one I made.

Russell.

Yes, you are correct - it was late and I missed out pi. Perhaps it would be better if I missed out on a few more pies!!

Very much agree.

What I have found running with just the injector was it's far to much and uses a lot of steam. The water level rises and I start to lose pressure. Shut the injector down at ~ 40 psi then the water drops - need more and the injector refuses to pick up. That's what I mean by "it was hard work driving"
Please don't get me wrong, the injectors are good and work well. I'd prefer to have a pump that pretty much looks after the boiler and use the injector only when needed.
I have a 16 oz (no. 2 ?) on there at the moment.

Good progress tonight. The brass is cut to size and roughed out. Decided to leave the bore Blind rather than make an end cap so drilled and reamed it 1/4" short. Still plenty of room for the ports.
All the drilling is done, Gland is made and holes tapped.

Alex,

if you want me to look at your injector and sort it out i would be happy to do so. it sounds like it is feeding way beyond the spec. not unusual im afraid on some of the cheaper stuff sold by the suppliers. it also should have a full operating range and feed down to 30psi/25psi.

unfortunately Simplex's (and Super Simplex's) cylinders are far too big in bore and encourage lazy driving as full working pressure isnt required, and the valve gear is a bit iffy leading to far less use of 'notching up' to save steam and run at a higher pressure.

the enlongated firebox on both also leads to a tendancy to have a fire that isnt radiant all the time, a fault of the Greenly locos designs. what Jim Ewins referred to as a 'lazy fire'.

you will gather from the above i am not a fan of Simplex or Super Simplex, always referred to in most clubs as 'Complex' instead of 'Simplex'. the axlepump design is but just one factor of this dislike.

cheers,

julian

Pump made, Tested and fitted.

It sucks water in on the Back Stroke as expected.
It blows water out on both forward and Back strokes. More on the forward than back.
I was able to generate just under 150 PSI of pressure with the pump. ​More than enough to feed the boiler.

Another issue was the Teflon Seal on the blowdown valve.
The Teflon squashed itself and you guessed it, refused to release.
New Blowdown made with a pipe for Boiler filling.

It's using an O ring which pushes inside a hole to produce the seal.

Quick Update.
Steamed her up at the wee​kend on Rollers.

New pump was a bit tight to start with. It soon bedded in.
Piston is a 3 part affair. PEEK Plastic ends with a Teflon seal held together with an M6 SS Nylock Nut on the 10mm piston rod. (I have Metric Reamers)
Pump Body and Gland are Brass. The bore is 16mm rather than 5/8 for the same reason.

The pump keeps up with the Boiler whilst on rollers. Will see next week if I get her onto the track how it works in real life.

Thanks again to everyone for your thoughts, comments and advice.